1. Field of the Invention
The present invention relates to a learning method for an article storage facility, more particularly, to a learning method for a facility having an article storage rack having article storage units arranged in a direction of rack lateral width and the vertical direction, a transporting device such as a vertically movable lift and a horizontal travel carriage, and an article transfer device supported by the transporting device.
2. Description of the Related Art
Such article storage facilities are configured to take articles in and out of storage units by moving an article support of article transfer means by a target distance in a fore and aft direction with respect to the rack with the article transfer means moved to the target stop position.
In such article storage facilities, because the target stop positions where the article transfer device is required to stop may be shifted in the direction of the rack lateral width, or the vertical direction with respect to the storage unit, and the target distances by which the article support is moved may be too large or small with respect to the distance from the article transfer device to the storage unit, due to positional variations of components that occur during assembly of the article storage rack and due to positional shifting of components in article transfer means, or the transporting device that occur with passage of time, it is necessary to correct target stop positions so that they become the proper positions for the storage units, and to correct the target distances so that they become the proper distances from the article transfer device to the storage units.
And a learning device in conventional article storage facilities includes a pair of imaging devices which are spaced apart from each other in the direction of the rack lateral width to capture an image of a detected member provided to each storage unit, and a learning control means for controlling the operation of the transporting device in order to move the article transfer means to target stop positions, for controlling the operation of the imaging device to capture the image of the detected member with the article transfer means located at the target stop position, and for correcting the target stop position and the target distance based on the image information of the image captured with the imaging device. The learning control means is configured to compute the three dimensional coordinates of the detected member based on the principle of stereovision from the parallax of the pair of pictures captured with the pair of imaging devices and to correct the target stop position in the rack lateral width direction and the vertical direction and the target distance based on this three-dimensional coordinates. (See, for example, JP Publication of Application No. 2001-158507.)
Incidentally, in the facilities in which the three-dimensional coordinates of the detected member are computed based on the principle of the stereo vision from the parallax of the pair of images as described above, the pair of imaging devices are either a pair of frontal view imaging devices which capture images of the detected member from the rack fore-and-aft direction, or a pair of angular view imaging devices which capture images of the detected member from the direction which is at an angle with respect to the rack fore-and-aft direction.
However, in the above-mentioned conventional article storage facilities, since the three-dimensional coordinates of the detected member are computed from the parallax of pair of images captured with the imaging devices based on the principle of the stereovision, and since the target stop position in the rack lateral width direction and the vertical direction and the target distance are corrected based on these three-dimensional coordinates, the calculations performed by the learning control means were complicated.